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Intro continued. Area of coverage. Kingdom Animalia Phylum Chordata Subphylum Urochordata (=Tunicata) Sea squirts, larvaceans, thaliaceans Subphylum Cephalochordata Amphioxus (lancelet) Subphylum Craniata (=Vertebrata of Haeckel) Hagfish (Mixini) Vertebrata. Deuterostomata.
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Area of coverage • Kingdom Animalia • Phylum Chordata • Subphylum Urochordata (=Tunicata) • Sea squirts, larvaceans, thaliaceans • Subphylum Cephalochordata • Amphioxus (lancelet) • Subphylum Craniata (=Vertebrata of Haeckel) • Hagfish (Mixini) • Vertebrata
Deuterostomata Pharyngotremata Echinodermata Hemichordata Chordata Somitichordata Amphioxus (Cephalochordata) Crinoids, Sea stars, etc Enteropneusta (Acorn worms) Protostome Invertebrates Tunicates (Tunicata) Craniates Pterobranchia
Protostome inverts • Deuterostome inverts
Hemichordata (incertae sedis)(=Enteropneusta) Acorn Worm Pterobranch
Pharyngeal (“gill”) slits • Opening from the gill chamber • Can include associated tissues • P. pouch – outpocketing of the gut • P. arch – tissues lying between P. slits
Urochordata (=Tunicata)Corella parallelograma Notochord – cordlike skeleton of the back
P. Chordata, Sp. CephalochordataAmphioxus Somites – rectangular shaped pairs of mesoderm on sides of notochord – gives rise to axial skeleton, muscles and dermis
Some Concept Review • Ideas of Darwin and Wallace • Evolutionary Developmental Concepts • Ontogeny: the history of an individual from initiation of cell division to death • Phylogeny: the evolutionary history of independent lineages or species
“Ontogeny recapitulates phylogeny” • Ernst Haeckel (1834-1919) • German anatomist • Embryonic stages of an animal reflect its evolutionary history 1874
Better explained by: • Von Baer’s “Law” (1828): General (primitive) features develop earlier in ontogeny than do special features (derived) that distinguish groups • Biogenetic “Law”: features that develop earliest in ontogeny are the oldest phylogenetically and features developing later in ontogeny are of more recent phylogenetic origin
A few notes on Patterns and Process in Evolution • Homology: • Analogy: • Homoplasy:
Cladistic Classification / Phylogenetic systematics • The science of evolutionary grouping based on shared derived characteristics • The naming of organisms based on these groups • Plesiomorphy: • Synapomorphy: • Autapomorphy: • Monophyly: • Paraphyly: • Polyphyly:
M N A B C Cladogram Branch Node Internode Root OTU Ingroup Outgroup Autapomorphy Plesiomorphy Synapomorphy